I am embroiled in a finger-pointing mess that I hope maybe someone can offer some insight into.
PBX: Iwatsu ECS with an ESNA Voicemail server
Lines: TW "POTs" lines coming in off a modem
Background: This is a campus where three branches are networked together to act as one system. The system has been installed for about 8 years and has just recently been upgraded. The only major change is that the voicemail ports now communicate over SIP instead of analog signaling. All calls are answered by the Auto Attendant.
Issue: Call comes into the auto attendant. The caller attempts to direct dial an extension, but intermittently (and often) an incoming digit is doubled. For example, if I dial 2218, extension 2221 is called.
ESNA Voicemail server troubleshooting: Wireshark capture shows that the AA is receiving the incorrect digits. It is not creating them.
Iwatsu ECS troubleshooting: The manufacturer states that the PBX is simply a pass-through device and it does not modify the DTMF at all. They suggest using a digit grabber to show that the incorrect digits are received from the carrier, but we do not have one.
Time Warner Response: Unfortunately we will not be able to see the extensions that are being dialed once the call is answered. Once it is answered it is seen as media streaming and we will treat it like a poor audio issue. If techs are not finding any signal issues to the modem problem will be in the PBX side...I can tell you that once the call is connected the DTMF tones are nothing more than sound over the media stream of the call, our phone switch would not interact with the tones at all, as it does not see them as tones, but rather a data stream.
They're asking me what other troubleshooting they should do. I'm primarily a programmer - not a field technician and I'm starting to pull out my hair. Any advice?